The present invention is generally directed to pin-clutch mechanisms and is particularly directed to an improvement in pin-clutch mechanisms of the type in which the pin is released from the clutch in response to application of a magnetic field. The present invention is further directed to an improvement in theft-deterrent devices of the type that include pin-clutch mechanisms.
Theft-deterrent devices are attached to articles, such as merchandise, for deterring the theft of such articles. Theft-deterrent devices of the type that contains a detrimental fluid substance that damages a protected article attached to the device by releasing such substance when the device is tampered with during an unauthorized attempt to remove the device from the article are described in U.S. patent application Ser. No. 07/360,842 filed June 1, 1989 by Lincoln H. Charlot, Jr. and Carter W. Clarke, Jr., in U.S. Pat. No. 4,944,075 filed Sept. 18, 1989 by Dennis L. Hogan and in U.S. Pat. No. 4,670,950 to Wisecup et al. Theft-deterrent devices of the type that function electronically to produce an alarm if an article to which the device is attached is removed from monitored premises without the device first being removed from the article are described in U.S. Pat. Nos. 4,481,428 to Lincoln H. Charlot, Jr.; 4,654,641 to Lucian G. Ferguson and Lincoln H. Charlot, Jr.; 4,670,740 to Fred Wade Herman and Lincoln H. Charlot, Jr.; and 4,727,360 to Lucian G. Ferguson and Lincoln H. Charlot, Jr.
Typically, the theft-deterrent device includes means for attaching the device to the article with the attaching means being embodied in two components that are adapted to be locked together on opposite sides of a portion of said article to prevent unauthorized removal of the device from the article. A typical attaching means includes a pin embodied in one of the two components and means embodied in the other component for receiving and clutching the pin. The device is attached to the protected article by passing the pin through a portion of the article and into the clutch of the other component.
A typical clutch mechanism for restraining a pin from longitudinal movement whereby the pin could not be removed from the other component in order to enable the theft deterrent device to be removed from the article includes a ferromagnetic anvil having an axial bore for axially receiving a pin; receiving means axially aligned with the anvil for axially receiving a said pin that is axially received by the bore of the anvil, wherein the anvil is longitudinally movable along its bore axis with respect to the receiving means; biasing means for forcing the anvil toward a first end of the receiving means; clutching means engaging the anvil and forced by the anvil toward the first end of the receiving means when the anvil is forced toward the first end of the receiving means by the biasing means, with the clutching means being disposed to apply radial pressure against said pin to firmly clutch the pin and thereby restrain said pin from longitudinal movement when the clutching means are forced toward the first end of the receiving means. In order to remove the pin from the clutch mechanism, magnetic flux is applied axially in relation to the anvil to force the anvil to move away from the first end of the receiving means. A clutch mechanism of this type that is used in theft deterrent devices is described in U.S. Pat. No. 4,523,356 to Lincoln H. Charlot, Jr.